Waste gas superheater



Q 1, 1932. L. A. MEHLER ET AL 1,881,815

WASTE GAS SUPERHEATER Filed Oct. 9. 1930 2 Sheets-Sheet l 0d. 11, 1932. L. A. MEHLER ET AL 1,881,815

WASTE GAS SUPERHEATER Filed Oct. 9, 1930 2 Sheets-Sheet 2 Patented Oct. 11, 1932 UNITED STATES LEO A. MEHLEB, OF EAST CHICAGO, INDIANA, AND ELLSWORTH J. WESTCO'IT, OF-

PATENT OFFICE I CHICAGO, ILLINOIS, ASSIGNORS TO FREYN ENGINEERING COMPANY, OF CHICAGO,

ILLINOIS, A CORPORATION OF MAINE WASTE GAS surnnnnnrnn Application filed October 9,1930. Serial No. 487,475.

This invention relates to superheaters and.

is illustrated as usedin connection with a waste heat boiler althoughit may be applied to other types of boilers and used generally for heat exchanging apparatus. In the generation of steam by the use of waste heat boilers large quantities of waste gases of comparatively low temperatures are used. In attempting to apply superheaters to this type of boiler a slightly different problem is presented because of the larger volume of gases and because the temperature difference between the waste gases and saturated steam is not as great as with other apparatus. This low temperature difference added to the large volume of gases necessitates a greater amount of heating surface in the superheater and heretofore a correspondingly large amount of space.

One object of this invention is to provide a superheater of greater eihciency and requiring less space than those heretofore known, especially when used with waste gas boilers.

Another object of the invention is to decrease the draft loss by diminishing the length of flue necessary to house the super heater.

An additional object of the invention is to provide a superheater in which the headers and units are away from the front of the boiler so that they may be out of the way when the boiler tubes are blown. As it is necessary to blow these tubes quite frequently, the matter of convenience and ready access is very important.

A further object of the invention is to provide a superheater unit. in which the pressure drop of the steam is at a minimum, considering the amount of heating surface.

Other objects of the invention will appear from the following description, drawings and claim.

' In the drawings, in which like numerals are used for similar parts throughout:

Figure 1 is a vertical sectional view of the apparatus taken along the line 1-1 of Figure 2;

Figure 2 is a side elevation of the superheater connected to the boiler; and

Figure is a fragmentary longitudinal section showing the superheater' units with the braces removed. a

' In the embodiment of the invention which has been illustrated by way of example, the superheater is located at the. front endo fthe boiler 10. The usual saturated steam connection 12 is used as well as the superheated steam outlet 14. 'Gonnectedfto the outlet 12.

is the 'saturated steam distributing header 16 and communicating with the connection 14 leaves the front unobstructed but it takes away from the front the extreme anddisagreeable heat which is necessarily found near these headers.

Each 'unit of the superheater includes two pipes 22 and 24. The pipes 22 and 24' lie in the same plane, the loop of one being betweenthe two legs of the loop of the other. If desired'one oribothpf the pipesmay be given a plurality of loops. In that case such double looppipe is preferably arranged'with first a'wide bend such as 26 and then a narrow bend such as 28, thus avoiding having two sharp bends adjacentto each other.

As illustrated in Figures 2 and 3, the pipes are quite close together, each being held in place by suitable braces 30. This closespacing is desirable in order to obtain a maximum of heating surface within a given space. In order to accomplish this the two pipes 22 and 24 are mounted on header 16 and likewise header 18 at the same longitudinal position, that is, they are spaced circumferentially but not longitudinally. I

A unit comprising two short pipes is much more eificient than would be a single pipe twice as long. A long single pipe in a space of the same width would necessarily have twice as many bends. To keep fromspread- 4e may be withdrawn between said headers ing over a greater length of passage each bend would have to be of the sharp type numbered 28. Thus the single double length pipe would. offer over twice as much resistance to steam flow, and as the cross-section would be only half that of two pipes, the pressure drop across the single pipe would be very much greater than across the two pipe unit of this invention.- 1

Any. number of units consisting'of pairs of pipes 22 and 24 may be used as dictated by V the amount of steam generated by the boiler. Then by knowing the temperature of the waste gases passing the superheater these 7 units may be made of justthe' right length to obtain the required heating surface to furnish superheat to the saturated steam generated by the boiler. a

Having thus described our invention, it is to be understoodfthat many other embodiments of theinvention, including some in improved form, will be apparent and in the course of time will be devised by those skilled in the art. Our invention includes all of these which come within the spirit of the following claim, construed as broadly as the prior art will permit. c 7

We claim: I 1

The combination of a waste gas boiler having tubes extending longitudinally therethrough, being adapted to have said tubes blown from the front end, and having an inlet fine at the front end; with a Waste gas superheater in said flue comprising headers I located at the side of said boiler and pairs of horizontally extending pipes in front of said boiler, the two pipes of each pair being U-shaped and connected in a single radial plane to each header, said headers being suf fieiently separated so that the U-shaped pipes while retained in their original planes.

Signed'at East Chicago, Indiana, this 30th day of September 1930.

LEO A. MEHLER.

' Signed at Chicago, Illinois, this 6th day of October 1930. V

V ELLSWORTH J. wEsTooTT. 

